Choking collar blowout preventer and stripper



Nov. 14, 1950 F. J. SCHWEITZER 2,529,744

CHOKING COLLAR BLOWOUT PREVENTER AND STRIPPER Filed May 18, 1946 INVENTOIQ,

WW /7w? [Sc/3106;261:623- 1 Patented Nov. 14, 1950 UNITED STATES PATENT OFFICE CHOKING COLLAR BLOWOUT PREVENTER AND STRIPPER Frank J. Schweitzer, Brea, Calif.

Application May 18, 1946, Serial No. 670,800

' 3 Claims. 1

This invention is a blow-out preventer and pipe stripper for deep well operations in which a string of connected pipe sections or other desired sections are employed me well casing.

In some wells gases or liquids or both may rise to such a pressure as to be a great hazard to the well equipment and operatives. It is an object of this invention to provide a simple, practical, substantial, reliable and effective blow-out preventer unit for fixation to the upper portion of the well casing for the axial passage and operation of the desired tool or other string and which unit includes a continuous, one+piece annular choke collar of contractive capacity to jam snugly onto the interposed string section to effectively seal oil the ascendingstream of fluid in the well casing.

A further object of the invention is to provide such a preventer and incorporate therein a bodily shiftable packer element a part of which consists of an inwardly arched choking collar, and in this connection an object is to provide a simple, dependable and effective means for both the advance of the packer in its containing shell for closure of the collar onto the string part, and for retraction of the collar and packer element at will.

Another object of the invention is to provide a tubular packer incorporating a contractive top end collar and which packer is of a suitably stilf or firm, but deformable material such as firm rubber or its equivalent so that the contracted collar feature will conform itself snugly onto the surface of the interposed string part to seal thereon. And with this it is an object of the invention to provide a firm, contractive diaphragm forming barrier device to reliably support the sealing collar in effective position and to provide for the cooperation of the barrier device and the collar so that they will move together to and from the sealing position.

The invention has for an additional object to provide a preventer of this type including means enabling the packing collar to function as a liquid stripper on the surface of the string of parts as the string may be pulled from the well, or be forced up in the casing by well fluid pressure, a purpose of the invention being to provide a cushioning capacity in the unit for automatic repression of the packer bodily since its material, say rubber, is not .sufiiciently intrinsically compressible.

The invention resides in certain advancements in this art as set forth in the ensuing disclosure and having with the above, additional objects and advantages as hereinafter developed, and whose constructions, combinations and details of means and the manner of operation will be made manifest in the following description of the herewith illustrative embodiment; it being understood that modifications, variations and adaptations may be resorted to within the scope, spirit and principle of the invention as it is claimed more directly in conclusion hereof.

Figure 1 is an elevation, partly in axial section, of the unit with the packer in fully open position, and

Figure 2 is a similar view with the packer in eifective, closed position on the string part.

Figure 3 is a plan showing a fragment of the barrier, diaphragm device in contracted position, and Fig. 4 is a side elevation of a toggle link forming a member of the diaphragm.

Figure 5 is a top end plan of the isolated packer the collar being fully open.

As illustrated, the preventer includes a generally cylindrical shell 2 closed at the bottom by a bolted flange 3 having a central boss 4 threadedly receiving the near end of a casing section C through which may pass and operate any suitable tool or other pipe or rod string S.

The upper end of the shell has a bolted bonnet ring 5 against the under face of which an annular system of pendent links 6 is abutted at pivot heels 1 of each link. The upper end of the shell is provided with an annular pocket 8 in which the links 6 normally hang in open position to widely clear the interposed string S. In edge View each link is shown as tapering wedgelike from its swinging or lower end so that the gang of links of the system may close contractively toward the string; Figs. 2 and 3.

The flange 3 has a rigid, upstanding bore wall 3a which terminates suitably below the links 6 to form an annular mouth 9 inwardly below an overhanging, inwardly arched, guide shoulder ll] of the shell 2, and in which mouth are ex- 1 posed portions of the curved, bottom ends 6a of the links which, in the idle position, Fig. 1, lie about flush with the bore face of the wall 3a.

The bore wall is spaced concentrically inward from the wall of the shell 2 to form an elongate, annular chamber [2 for the reception of a complementary, annular, tubular packer i 3 whose upper end has an inwardly arched collar or top end I3a snugly fitting in the mouth 9 opening to the bore space of the wall 311; the end face of the packer collar continuing the bore space in the unit. The upper surface of the collar is constantly engaged by the near end faces of the diaphragm links 6 and to insure a coaction of the link system to form a closed diaphragm, at times, the link ends have spurs lb interhooking in the packer end portion.

The packer I3 is bodily shiftable in the chamber 12 for the purpose of forcibl ramming the collar l3a centrally in toward and into engagement with the interposed string S when necessary to positively close ofi the flow bore against rising well fluids.

The lower end of the packer I3 is rigidly anchored at M to the upper end of a ring-like piston l slidabl fitting in the chamber [2 and which may be actuated by any suitable means.

Preferably the piston is actuated by fluid pressure from an convenient source as by way of a fluid pressure pipe I 6 tapping the flange 3 to force the piston upward to shift the packer and contract its top end.

A fluid pressure pipe i l taps the shell 2 to supply fluid to a. reversing pressure chamber 13 of the shell in which is exposed the upper face of a piston shoulder l5a.

This preventer has the further function of forming a stripper when the string S is moved upwardly in the casing C when the packer collar has first been contracted onto the string to seal on it. Since the packer material is too firm to be compressible within its own bulk the whole packer element is here adapted to bodily recede in the event that a pipe string coupling s should move into irresistible contact with the closed collar 83a while buttressed by the link diaphragm; which itself will allow the coupling to pass when the collar is repressed. The piston I5 is therefore made hollow to provide an air trap I51. and

if the motive-agent is a liquid the trapped air will the compacted, closed collar onto the string part What is claimed is:

1. A blow-out preventer and pipe stripper including a casing head shell having a cylindric bore face with a fixed inwardly guide arch at its upper end, an inner tubular wall spaced from and concentric with said bore face and in which a tool string having a shoulder projection may pass axially, a tubular, flexible packer fitted and bodily endwise movable in the space between said bore face and said wall and which is directed by said arch inwardly toward an interposed tool string, a pressure operated piston means connected to and for bodily shifting the acker to extrude it from said space at the upper end, and a buttress means normally pocketed in open position in the shell and being moved centripetally onto the top surface of and b and as the upper end of the packer is extruded from said guide arch.

2. A blow-out preventer including a shell and an attached casing head flange, a tubular, flexible packer fitted in the bore of the shell, a fixed inwardly directed arch in the shell, a central, tubular wall fixed to said flange and fitting in said packer, a piston operatively fitted on said wall and connected to said packer for forcibly extruding it past said arch toward a tool string when the same is interposed in the said tubular wall, and an abutment device normally retracted in open position above said arch and away from the upper end of the packer, and being centripetally contractive by and to support the inwardly extruded upper end of the packer, means operatively connecting the packer and the said device, and pressure means for double action effort on the piston.

'3. The preventer of claim 2'; the said abutment device consisting of pendent, diaphragm sections which recede from the upper end of the packer as it is retracted by a reverse action of the piston.

FRANK J. SCHWEIT-ZER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,148,844 Stone et al. Feb. 28, 1939 2,287,205 Stone June 23, 1942 2,332,763 Stewart Oct. 26, 1943 

